When we get to heaven, our human nature will be changed.  In this life we have an imperfect human nature; a sinful human nature.  In the next life, however, we will have a perfect human nature as Christ Jesus has; a sinless human nature.¹  It is important to note that Christ Jesus is different from us in that within Him dwells perfect humanity ( a sinless human nature) and Divinity; He is God-man.

As to memories having sin in them; memories are not sin.  Sin comes about when one gives into temptation, and given the opportunity, would act upon it.²

Both the righteous and the un-righteous will retain their memories in the next life.

Bible References:

¹ ( 1 John 3:2; 1 Corinthians 15:49)

² (James 1:13-15)